As a participating institution in the Primary Breast Cancer Therapy Group (NSABP), we are contributing data from patients entered into Protocol Nos. 4,6,8,9,10 of the group. The present application seeks funding (a) to permit continued patient accrual in ongoing protocols, (Nos. 6,9 and 10) (b) to continue follow-up of patients entered into protocols which have terminated, (Nos. 4 and 8) and (c) to collect appropriate biological material and information relevant to such protocols. The ongoing protocols are: (1) No.6: A trial to compare the worth of segmental mastectomy with and without breast radiation with total mastectomy plus axillary dissection. All patients will undergo axillary dissection and those with histologically positive axillary nodes will receive adjuvant chemotherapy. (2) No. 9: A trial to determine whether the anti-estrogen Tamoxifen when combined with chemotherapy improves the results obtained with chemotherapy alone in the adjuvant therapy of Stage II breast cancer. (3) No. 10: A trial to compare the value of the immunopotentiator C. parvum combined with chemotherapy vs. chemotherapy alone in the adjuvant therapy of Stage II breast cancer. We will participate in new NSABP protocols now being designed, e.g., an adjuvant therapy protocol for breast cancer patients with negative axillary nodes and a protocol to evaluate various treatment modalities in the management of patients with Stage III breast cancer.